1. Field
The invention relates to a thin film transistor. More particularly, the invention relates to a thin film transistor including an oxide semiconductor, a display substrate including the thin film transistor and a method of manufacturing the thin film transistor.
2. Description of Related Art
Generally, a thin film transistor for driving a pixel in a display device includes a gate electrode, a source electrode, a drain electrode, and an active pattern forming a channel between the source electrode and the drain electrode. The active pattern includes a semiconductor layer including amorphous silicon, polycrystalline silicon, oxide semiconductor, or the like.
Amorphous silicon has a relatively low electron mobility, which may be about 1 square centimeter per volt second (cm2/V·s) to about 10 cm2/V·s, so that a thin film transistor including amorphous silicon has relatively low driving characteristics. In contrast, polycrystalline silicon has a relatively high electron mobility, which may be about 10 cm2/V to about hundreds cm2/V. However, a crystallization process is required for forming polycrystalline silicon. Thus, forming a uniform polycrystalline silicon layer on a large-sized substrate may be difficult, and resulting manufacturing costs are high. Oxide semiconductors may be formed through a low-temperature process, may be easily formed in a large-scale, and have a high electron mobility. Thus, research is actively being conducted on thin film transistors which include an oxide semiconductor.